Geochemical constraints on the tectonic environment of ~1.8 Ga mafic dyke swarms in the North China Craton

Early Precambrian mafic dykes in western Shandong province, North China Craton: constraints on the chronology, genetic model and tectonic significance

“…In general, mafic dyke swarms can provide significant scientific information for the time and stage of extensional tectonics, and are ideal objects for studying mantle plume activity and lithospheric extension (Hou, 2012). Previous studies in the NCC focused on Mesozoic, Cenozoic and Proterozoic mafic dykes and documented three episodes of lithospheric extension during the Proterozoic (i.e.…”

“…The NCC is composed of uniform Precambrian crystalline basement, which is covered by younger overburden (Zhao et al 2001) and invaded by the Precambrian and Mesozoic mafic dyke swarms (e.g. Li et al 1997; Zhai and Bian, 2000; Hou et al 2004, 2006; Liu et al 2004, 2005, 2008 a , b , 2009, 2012 a , b , 2013 b ; Peng et al 2005, 2007, 2008, 2010, 2011 a , b ; Peng, 2010; Hou, 2012). Another model suggests that the NCC is composed of several Archaean micro-continental blocks and these blocks have been proliferated into large continental fragments (Zhai & Bian, 2000; Zhao, 2009; Zhai & Santosh, 2011; Dan et al 2012, 2014; Zhang et al 2013; Yang et al 2016; Yang & Santosh, 2017).…”

“…To date, more than 100 Proterozoic (<2.5 Ga) mafic dykes have been found in the NCC including those in the Hebei, Shanxi and Shandong area with ages ranging from 800 to 600 Ma, 820 Ma, 900 Ma, 925 Ma, 1.78 Ga and 2.4 to 1.6 Ga. They have been widely studied (Li et al 1997; Zhai & Bian, 2000; Peng et al 2005, 2007, 2008, 2010, 2011 a , b ; Hou et al 2006; Peng, 2010; Hou, 2012; Li, 2014). Nevertheless, only a few investigations of the Archaean mafic dykes (>2.5 Ga) have been carried out in the NCC.…”

“…At present, the western part of Shandong province has been the focus of several studies related to the Early Precambrian evolutionary history of the NCC (Hou, 2012). Approximately 95 % of the Early Precambrian crystalline basement in western Shandong is dominated by granulites, greenstones, Trondhjemite-Tonalite-Granodiorite (TTG) gneisses, gneissic monzogranite, dioritic to granodioritic intrusions, and mafic dyke swarms (Wang, 1990; Hou et al 2004; Ju et al .…”

“…In addition, the TTG series rocks and gneissic monzogranites in this area have been divided into two stages (2.5–2.6 Ga, 2.45–2.56 Ga; Jahn, 1988; Wang, 1991, 1993). The mafic dykes in western Shandong province are generally NE–SW-trending and are mainly located in the Tai’an, Laiwu and Mengyin regions (Hou, 2012).…”